Method and apparatus for reeling discrete yarn strand patterns

Abstract

Method and apparatus for continuously monitoring a moving yarn line to detect the presence of undesired denier imperfections. The yarn is passed through an elongated constricted passage sensing device into which a sensing fluid is concurrently fed. The back pressure thus created in the fluid carrying line due to flow resistance in the sensing device, is monitored to detect variations which would indicate an imperfection in the moving yarn line.

I claim: 
     
       1. Yarn grading apparatus for monitoring a moving yarn line comprising one or more discrete strands to assure the denier consistency thereof, the apparatus including: means forming an elongated sensing passage of sufficient cross sectional opening to closely surround a segment of said moving yarn line, whereby to define an elongated annular chamber between said yarn line and the walls of said sensing passage when said line segment is registered within said elongated sensing passage,   said means forming a sensing passage including a holder comprising elongated upper and lower members being pivotally engaged along a mutual edge thereof to permit pivotal movement of the respective members between open and closed positions, each of said upper and lower members having a cavity therein disposed in contiguous relationship when said respective members are in the closed position,   passage defining inserts (21 and 22) removably positioned within the respective cavities whereby to define said elongated sensing passage about said yarn line when the holder is in the closed position,   a source of sensing fluid including at least one conduit communicating said sensing fluid source with said elongated annular chamber to introduce a controlled flow of sensing fluid to the latter, whereby to establish a fluid back pressure within said at least one conduit and said annular chamber as a result of the fluid flow resistance characteristics exhibited by said annular chamber, and   monitoring means communicated with said at least one conduit, being sensitive to the occurrence of variations in the magnitude of the said fluid back pressure, which occur in response to a change in fluid flow resistance within said annular chamber.   
     
     
       2. The apparatus as defined in claim 1, wherein said passage defining inserts (21 and 22) are formed of an abrasion resistant material. 
     
     
       3. The apparatus as defined in claim 2, wherein said sensing passage defined by said passage defining inserts extends substantially the longitudinal length of said holder. 
     
     
       4. The apparatus as defined in claim 1, wherein the ratio of said sensing passage length, to the cross sectional area thereof normal to said passage length, is approximately 400 to 1. 
     
     
       5. The apparatus as defined in claim 1, wherein said passage defining inserts (21 and 22) are formed of aluminum oxide. 
     
     
       6. The apparatus as defined in claim 1, wherein said passage defining inserts (21 and 22) are formed of tungsten carbide. 
     
     
       7. The apparatus as defined in claim 2, wherein said passage defining inserts are formed of a plurality of said members removably positioned within a common holder cavity whereby to define a curved wall of said elongated sensing passage.